Verify the identity-   tan (x-(3pi/2))=-cotx  PLEASE ANSWER QUICKLY. I have a test tomorrow!

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neela | High School Teacher | (Level 3) Valedictorian

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To verify tan (x-3pi/2) = -cotx.


Consider the left side:

Tan (x-3pi/2) =  Tan (x-3pi +2pi) as tan function is 2pi periodic.


= - tan (supplementary angle of x+Pi/2)

= -tan (pi/2-x)

=-cotx = RHS,  as in triangle ABC with B as triangle, and A as x+pi/2, and C as pi/2 - x, tanA = cotB. Or Tan (x+pi) = cot(pi-x).

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